I N PREVIOUS work, it was found that the ‘osmotic ceiling’ in the urine from the desert rodents Heteromyidae is exceptionally high compared with the osmotic ceiling in urine from other mammals. This mechanism is of importance to water conservation. The general objective of the further investigations was to find in what respects the function of the heteromyid kidney differs from that of other ma...

For determination of the dynamics of parotid urea secretion in conscious sheep, a previously standardized transit time ultrasonic flow metering system was used to measure bilateral parotid flow. Six ewes fed for ad libitum consumption were prepared under halothane anesthesia with ultrasonic probes around both parotid ducts; these ducts were also cannulated orally. After probe encapsulation (8 d...

Exhaled breath condensate (EBC) analyses promise simple and noninvasive methods to measure airway biomarkers but pose considerable methodological challenges. We utilized mass spectrometry to measure EBC purine biomarkers adenosine and AMP plus urea to control for dilutional variability in two studies: 1) a cross-sectional analysis of 28 healthy, 40 cystic fibrosis (CF), and 11 asthmatic childre...

The objective was to evaluate the effect of replacing common urea with protected in supplement on nutrient intake and digestibility metabolic profile sheep. Five adult sheep, an average age 4 years initial body weight 50 ± 4.03 kg, were used. diet consisted sorghum silage, supplemented a multiple mixture corn bran, soybean meal, white salt, mineral (CU) or (PU). experimental design 5x5 Latin sq...

Experiments characterizing the urea active transport system in Saccharomyces cerevisiae indicate that (i) formamide and acetamide are strong competitive inhibitors of urea accumulation, (ii) uptake is maximal at pH 3.3 and is 80% inhibited at pH 6.0, and (iii) adenosine 5'-triphosphate generated by glycolysis in conjunction with formation of an ion gradient is likely the driving force behind ur...